Update 4_vector_spaces_QM.md

src/4_vector_spaces_QM.md

@@ -132,8 +132,8 @@ $$
 \langle \chi|\psi\rangle=
 \langle\chi|\hat{I} |\psi\rangle=\sum_{i=1}^n \langle\chi| \phi_i \rangle \langle\phi_i|\psi\rangle \, .
 $$
-Next, using that $\chi_n = \langle \phi_i|\chi \rangle$ are the components of the
-state vector $|\chi\rangle$ and that  $\langle \chi| \phi_n \rangle=(\langle\phi_n|\chi\rangle)^*$,
+Next, using that $\chi_i = \langle \phi_i|\chi \rangle$ are the components of the
+state vector $|\chi\rangle$ and that  $\langle \chi| \phi_n \rangle=(\langle\phi_i|\chi\rangle)^*$,
 we have that $\langle \chi |\phi_i\rangle =\chi_i^*$
 and therefore the inner product of the two state vectors $|\psi\rangle$
 and  $|\chi\rangle$ can be expressed in terms of their components